TY - GEN
T1 - Disk schedulers for solid state drivers
AU - Kim, Jaeho
AU - Oh, Yongseok
AU - Kim, Eunsam
AU - Choi, Jongmoo
AU - Lee, Donghee
AU - Noh, Sam H.
PY - 2009
Y1 - 2009
N2 - In embedded systems and laptops, flash memory storage such as SSDs (Solid State Drive) have been gaining popularity due to its low energy consumption and durability. As SSDs are flash memory based devices, their performance behavior differs from those of magnetic disks. However, little attention has been paid on how to exploit SSDs from the disk scheduling algorithm view point. In this paper, we first describe behaviors of SSDs that inspires us to design a new disk scheduler for the Linux operating system. Specifically, read service time is almost constant in an SSD while write service time is not. Moreover, appropriate grouping of write requests eliminates any ordering-related restrictions and also maximizes write performance. From these observations, we propose two disk schedulers: IRBW-FIFO and IRBW-FIFO-RP. Both schedulers arrange write requests into bundles of an appropriate size while read requests are independently scheduled. Then, the IRBW-FIFO scheduler provides complete FIFO ordering to each bundle of write requests and each individual read requests while the IRBW-FIFO-RP scheduler gives higher priority to read requests than the bundles of write requests. We implement these schedulers in Linux 2.6.23, and results of executing our set of benchmark programs shows that performance improvements of up to 17% compared to existing Linux disk schedulers are achieved.
AB - In embedded systems and laptops, flash memory storage such as SSDs (Solid State Drive) have been gaining popularity due to its low energy consumption and durability. As SSDs are flash memory based devices, their performance behavior differs from those of magnetic disks. However, little attention has been paid on how to exploit SSDs from the disk scheduling algorithm view point. In this paper, we first describe behaviors of SSDs that inspires us to design a new disk scheduler for the Linux operating system. Specifically, read service time is almost constant in an SSD while write service time is not. Moreover, appropriate grouping of write requests eliminates any ordering-related restrictions and also maximizes write performance. From these observations, we propose two disk schedulers: IRBW-FIFO and IRBW-FIFO-RP. Both schedulers arrange write requests into bundles of an appropriate size while read requests are independently scheduled. Then, the IRBW-FIFO scheduler provides complete FIFO ordering to each bundle of write requests and each individual read requests while the IRBW-FIFO-RP scheduler gives higher priority to read requests than the bundles of write requests. We implement these schedulers in Linux 2.6.23, and results of executing our set of benchmark programs shows that performance improvements of up to 17% compared to existing Linux disk schedulers are achieved.
KW - Disk scheduler
KW - Implementation study
KW - Linux
KW - Solid state drive
UR - http://www.scopus.com/inward/record.url?scp=72249108161&partnerID=8YFLogxK
U2 - 10.1145/1629335.1629375
DO - 10.1145/1629335.1629375
M3 - Conference contribution
AN - SCOPUS:72249108161
SN - 9781605586274
T3 - Embedded Systems Week 2009 - Proceedings of the 7th ACM International Conference on Embedded Software, EMSOFT '09
SP - 295
EP - 304
BT - Embedded Systems Week 2009 - Proceedings of the 7th ACM International Conference on Embedded Software, EMSOFT '09
T2 - Embedded Systems Week 2009, ESWEEK 2009 - 7th ACM International Conference on Embedded Software, EMSOFT '09
Y2 - 11 October 2009 through 16 October 2009
ER -